Apparatus for pocketed coil construction having improved tracking characteristics

Abstract

Improvements to a method and apparatus are disclosed for making a series of coil springs pocketed within individual pockets in an elongate fabric strip comprised of two overlying plies capable of being welded together. Improvements include improvements to fabric tracking and folding, fabric handling along the fabric path, and various direct-drive configuration eliminating the need for pneumatic cylinders.

What is claimed is: 
     
       1. An apparatus for manufacturing a pocketed innerspring construction for a mattress comprising: (a) means for drawing a length of fabric having a substantially uniform width from a roll of said fabric;   (b) a folding plate having a substantially horizontal, planar surface extending from an upstream end thereof to a downstream end, said downstream end of said surface having tapering lead folding edges converging at a downstream end point;   (c) means for urging said length of fabric from said upstream end to said downstream end of said surface and for causing said fabric to pass over said folding edges on the downstream end of said surface with the downstream end point essentially in contact with the center of said fabric width so that said fabric folds substantially in half along its length with the width of the folded fabric being substantially one-half of the width of the fabric and with the two free longitudinal edges of said fabric being in general alignment;   (d) a pair of inwardly-biased, pivotably mounted folding fingers positioned below said surface and having a gap therebetween to receive said folded fabric passing over said folding edges of said surface, said folding fingers being structured to pinch together to maintain a bias against fabric passing therebetween to enable accurate folding of said fabric with said longitudinal edges being in substantial registration and alignment;   (e) means for inserting coil springs between said folded fabric halves and for joining said fabric in a manner such that said coil springs are contained within pockets in said fabric; and   (f) means for connecting said pocketed coil springs together to form an innerspring construction.   
     
     
       2. The apparatus of claim 1 wherein said tapering lead folding edges of said downstream end of said surface converge at said downstream end point at a taper angle in excess of 90 degrees. 
     
     
       3. The apparatus of claim 2 wherein said taper angle is about 94 degrees. 
     
     
       4. The apparatus of claim 1 wherein at least one of said folding fingers is spring biased causing the folding fingers to pinch together to maintain said bias against folded fabric passing therebetween. 
     
     
       5. The apparatus of claim 1 wherein said folding fingers are independently spring-biased. 
     
     
       6. The apparatus of claim 1 including a fabric edge guide assembly for adjusting the position of the longitudinal edges of said length of fabric on said folding plate to assure that the fabric passes over the folding edges of the planar surface in proper alignment with the downstream end point of said surface essentially in contact with said center of said fabric width. 
     
     
       7. The apparatus of claim 6 wherein said fabric edge guide assembly is mounted above said folding plate in position to engage the fabric as it passes over said substantially horizontal, planar surface from said upstream end to said downstream end thereof.